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abd71baa DL |
1 | /* |
2 | * Copyright (c) 2019 David Lamparter, for NetDEF, Inc. | |
3 | * | |
4 | * Permission to use, copy, modify, and distribute this software for any | |
5 | * purpose with or without fee is hereby granted, provided that the above | |
6 | * copyright notice and this permission notice appear in all copies. | |
7 | * | |
8 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES | |
9 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF | |
10 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR | |
11 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
12 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | |
13 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF | |
14 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
15 | */ | |
16 | ||
17 | #include <stdlib.h> | |
18 | #include <string.h> | |
19 | ||
20 | #include "typesafe.h" | |
21 | #include "memory.h" | |
22 | ||
23 | DEFINE_MTYPE_STATIC(LIB, TYPEDHASH_BUCKET, "Typed-hash bucket") | |
24 | DEFINE_MTYPE_STATIC(LIB, SKIPLIST_OFLOW, "Skiplist overflow") | |
25 | ||
26 | #if 0 | |
27 | static void hash_consistency_check(struct thash_head *head) | |
28 | { | |
29 | uint32_t i; | |
30 | struct thash_item *item, *prev; | |
31 | ||
32 | for (i = 0; i < HASH_SIZE(*head); i++) { | |
33 | item = head->entries[i]; | |
34 | prev = NULL; | |
35 | while (item) { | |
36 | assert(HASH_KEY(*head, item->hashval) == i); | |
37 | assert(!prev || item->hashval >= prev->hashval); | |
38 | prev = item; | |
39 | item = item->next; | |
40 | } | |
41 | } | |
42 | } | |
43 | #else | |
44 | #define hash_consistency_check(x) | |
45 | #endif | |
46 | ||
47 | void typesafe_hash_grow(struct thash_head *head) | |
48 | { | |
49 | uint32_t newsize = head->count, i, j; | |
50 | uint8_t newshift, delta; | |
51 | ||
52 | hash_consistency_check(head); | |
53 | ||
54 | newsize |= newsize >> 1; | |
55 | newsize |= newsize >> 2; | |
56 | newsize |= newsize >> 4; | |
57 | newsize |= newsize >> 8; | |
58 | newsize |= newsize >> 16; | |
59 | newsize++; | |
60 | newshift = __builtin_ctz(newsize) + 1; | |
61 | ||
62 | if (head->maxshift && newshift > head->maxshift) | |
63 | newshift = head->maxshift; | |
64 | if (newshift == head->tabshift) | |
65 | return; | |
66 | newsize = _HASH_SIZE(newshift); | |
67 | ||
68 | head->entries = XREALLOC(MTYPE_TYPEDHASH_BUCKET, head->entries, | |
69 | sizeof(head->entries[0]) * newsize); | |
70 | memset(head->entries + HASH_SIZE(*head), 0, | |
71 | sizeof(head->entries[0]) * | |
72 | (newsize - HASH_SIZE(*head))); | |
73 | ||
74 | delta = newshift - head->tabshift; | |
75 | ||
76 | i = HASH_SIZE(*head); | |
77 | if (i == 0) | |
78 | goto out; | |
79 | do { | |
80 | struct thash_item **apos, *item; | |
81 | ||
82 | i--; | |
83 | apos = &head->entries[i]; | |
84 | ||
85 | for (j = 0; j < (1U << delta); j++) { | |
86 | item = *apos; | |
87 | *apos = NULL; | |
88 | ||
89 | head->entries[(i << delta) + j] = item; | |
90 | apos = &head->entries[(i << delta) + j]; | |
91 | ||
92 | while ((item = *apos)) { | |
93 | uint32_t midbits; | |
94 | midbits = _HASH_KEY(newshift, item->hashval); | |
95 | midbits &= (1 << delta) - 1; | |
96 | if (midbits > j) | |
97 | break; | |
98 | apos = &item->next; | |
99 | } | |
100 | } | |
101 | } while (i > 0); | |
102 | ||
103 | out: | |
104 | head->tabshift = newshift; | |
105 | hash_consistency_check(head); | |
106 | } | |
107 | ||
108 | void typesafe_hash_shrink(struct thash_head *head) | |
109 | { | |
110 | uint32_t newsize = head->count, i, j; | |
111 | uint8_t newshift, delta; | |
112 | ||
113 | hash_consistency_check(head); | |
114 | ||
115 | if (!head->count) { | |
116 | XFREE(MTYPE_TYPEDHASH_BUCKET, head->entries); | |
117 | head->tabshift = 0; | |
118 | return; | |
119 | } | |
120 | ||
121 | newsize |= newsize >> 1; | |
122 | newsize |= newsize >> 2; | |
123 | newsize |= newsize >> 4; | |
124 | newsize |= newsize >> 8; | |
125 | newsize |= newsize >> 16; | |
126 | newsize++; | |
127 | newshift = __builtin_ctz(newsize) + 1; | |
128 | ||
129 | if (head->minshift && newshift < head->minshift) | |
130 | newshift = head->minshift; | |
131 | if (newshift == head->tabshift) | |
132 | return; | |
133 | newsize = _HASH_SIZE(newshift); | |
134 | ||
135 | delta = head->tabshift - newshift; | |
136 | ||
137 | for (i = 0; i < newsize; i++) { | |
138 | struct thash_item **apos = &head->entries[i]; | |
139 | ||
140 | for (j = 0; j < (1U << delta); j++) { | |
141 | *apos = head->entries[(i << delta) + j]; | |
142 | while (*apos) | |
143 | apos = &(*apos)->next; | |
144 | } | |
145 | } | |
146 | head->entries = XREALLOC(MTYPE_TYPEDHASH_BUCKET, head->entries, | |
147 | sizeof(head->entries[0]) * newsize); | |
148 | head->tabshift = newshift; | |
149 | ||
150 | hash_consistency_check(head); | |
151 | } | |
152 | ||
153 | /* skiplist */ | |
154 | ||
155 | static inline struct sskip_item *sl_level_get(struct sskip_item *item, | |
156 | size_t level) | |
157 | { | |
158 | if (level < SKIPLIST_OVERFLOW) | |
159 | return item->next[level]; | |
160 | if (level == SKIPLIST_OVERFLOW && !((uintptr_t)item->next[level] & 1)) | |
161 | return item->next[level]; | |
162 | ||
163 | uintptr_t ptrval = (uintptr_t)item->next[SKIPLIST_OVERFLOW]; | |
164 | ptrval &= UINTPTR_MAX - 3; | |
165 | struct sskip_overflow *oflow = (struct sskip_overflow *)ptrval; | |
166 | return oflow->next[level - SKIPLIST_OVERFLOW]; | |
167 | } | |
168 | ||
169 | static inline void sl_level_set(struct sskip_item *item, size_t level, | |
170 | struct sskip_item *value) | |
171 | { | |
172 | if (level < SKIPLIST_OVERFLOW) | |
173 | item->next[level] = value; | |
174 | else if (level == SKIPLIST_OVERFLOW && !((uintptr_t)item->next[level] & 1)) | |
175 | item->next[level] = value; | |
176 | else { | |
177 | uintptr_t ptrval = (uintptr_t)item->next[SKIPLIST_OVERFLOW]; | |
178 | ptrval &= UINTPTR_MAX - 3; | |
179 | struct sskip_overflow *oflow = (struct sskip_overflow *)ptrval; | |
180 | oflow->next[level - SKIPLIST_OVERFLOW] = value; | |
181 | } | |
182 | } | |
183 | ||
184 | struct sskip_item *typesafe_skiplist_add(struct sskip_head *head, | |
185 | struct sskip_item *item, | |
186 | int (*cmpfn)(const struct sskip_item *a, | |
187 | const struct sskip_item *b)) | |
188 | { | |
189 | size_t level = SKIPLIST_MAXDEPTH, newlevel, auxlevel; | |
190 | struct sskip_item *prev = &head->hitem, *next, *auxprev, *auxnext; | |
191 | int cmpval; | |
192 | ||
193 | /* level / newlevel are 1-counted here */ | |
194 | newlevel = __builtin_ctz(random()) + 1; | |
195 | if (newlevel > SKIPLIST_MAXDEPTH) | |
196 | newlevel = SKIPLIST_MAXDEPTH; | |
197 | ||
198 | next = NULL; | |
199 | while (level >= newlevel) { | |
200 | next = sl_level_get(prev, level - 1); | |
201 | if (!next) { | |
202 | level--; | |
203 | continue; | |
204 | } | |
205 | cmpval = cmpfn(next, item); | |
206 | if (cmpval < 0) { | |
207 | prev = next; | |
208 | continue; | |
209 | } else if (cmpval == 0) { | |
210 | return next; | |
211 | } | |
212 | level--; | |
213 | } | |
214 | ||
215 | /* check for duplicate item - could be removed if code doesn't rely | |
216 | * on it, but not really work the complication. */ | |
217 | auxlevel = level; | |
218 | auxprev = prev; | |
219 | while (auxlevel) { | |
220 | auxlevel--; | |
221 | auxnext = sl_level_get(auxprev, auxlevel); | |
222 | cmpval = 1; | |
223 | while (auxnext && (cmpval = cmpfn(auxnext, item)) < 0) { | |
224 | auxprev = auxnext; | |
225 | auxnext = sl_level_get(auxprev, auxlevel); | |
226 | } | |
227 | if (cmpval == 0) | |
228 | return auxnext; | |
229 | }; | |
230 | ||
231 | head->count++; | |
232 | memset(item, 0, sizeof(*item)); | |
233 | if (newlevel > SKIPLIST_EMBED) { | |
234 | struct sskip_overflow *oflow; | |
235 | oflow = XMALLOC(MTYPE_SKIPLIST_OFLOW, sizeof(void *) | |
236 | * (newlevel - SKIPLIST_OVERFLOW)); | |
237 | item->next[SKIPLIST_OVERFLOW] = (struct sskip_item *) | |
238 | ((uintptr_t)oflow | 1); | |
239 | } | |
240 | ||
241 | sl_level_set(item, level, next); | |
242 | sl_level_set(prev, level, item); | |
243 | /* level is now 0-counted and < newlevel*/ | |
244 | while (level) { | |
245 | level--; | |
246 | next = sl_level_get(prev, level); | |
247 | while (next && cmpfn(next, item) < 0) { | |
248 | prev = next; | |
249 | next = sl_level_get(prev, level); | |
250 | } | |
251 | ||
252 | sl_level_set(item, level, next); | |
253 | sl_level_set(prev, level, item); | |
254 | }; | |
255 | return NULL; | |
256 | } | |
257 | ||
258 | /* NOTE: level counting below is 1-based since that makes the code simpler! */ | |
259 | ||
260 | struct sskip_item *typesafe_skiplist_find(struct sskip_head *head, | |
261 | const struct sskip_item *item, int (*cmpfn)( | |
262 | const struct sskip_item *a, | |
263 | const struct sskip_item *b)) | |
264 | { | |
265 | size_t level = SKIPLIST_MAXDEPTH; | |
266 | struct sskip_item *prev = &head->hitem, *next; | |
267 | int cmpval; | |
268 | ||
269 | while (level) { | |
270 | next = sl_level_get(prev, level - 1); | |
271 | if (!next) { | |
272 | level--; | |
273 | continue; | |
274 | } | |
275 | cmpval = cmpfn(next, item); | |
276 | if (cmpval < 0) { | |
277 | prev = next; | |
278 | continue; | |
279 | } | |
280 | if (cmpval == 0) | |
281 | return next; | |
282 | level--; | |
283 | } | |
284 | return NULL; | |
285 | } | |
286 | ||
287 | struct sskip_item *typesafe_skiplist_find_gteq(struct sskip_head *head, | |
288 | const struct sskip_item *item, int (*cmpfn)( | |
289 | const struct sskip_item *a, | |
290 | const struct sskip_item *b)) | |
291 | { | |
292 | size_t level = SKIPLIST_MAXDEPTH; | |
293 | struct sskip_item *prev = &head->hitem, *next; | |
294 | int cmpval; | |
295 | ||
296 | while (level) { | |
297 | next = sl_level_get(prev, level - 1); | |
298 | if (!next) { | |
299 | level--; | |
300 | continue; | |
301 | } | |
302 | cmpval = cmpfn(next, item); | |
303 | if (cmpval < 0) { | |
304 | prev = next; | |
305 | continue; | |
306 | } | |
307 | if (cmpval == 0) | |
308 | return next; | |
309 | level--; | |
310 | } | |
311 | return next; | |
312 | } | |
313 | ||
314 | struct sskip_item *typesafe_skiplist_find_lt(struct sskip_head *head, | |
315 | const struct sskip_item *item, int (*cmpfn)( | |
316 | const struct sskip_item *a, | |
317 | const struct sskip_item *b)) | |
318 | { | |
319 | size_t level = SKIPLIST_MAXDEPTH; | |
320 | struct sskip_item *prev = &head->hitem, *next, *best = NULL; | |
321 | int cmpval; | |
322 | ||
323 | while (level) { | |
324 | next = sl_level_get(prev, level - 1); | |
325 | if (!next) { | |
326 | level--; | |
327 | continue; | |
328 | } | |
329 | cmpval = cmpfn(next, item); | |
330 | if (cmpval < 0) { | |
331 | best = prev = next; | |
332 | continue; | |
333 | } | |
334 | level--; | |
335 | } | |
336 | return best; | |
337 | } | |
338 | ||
339 | void typesafe_skiplist_del(struct sskip_head *head, struct sskip_item *item, | |
340 | int (*cmpfn)(const struct sskip_item *a, | |
341 | const struct sskip_item *b)) | |
342 | { | |
343 | size_t level = SKIPLIST_MAXDEPTH; | |
344 | struct sskip_item *prev = &head->hitem, *next; | |
345 | int cmpval; | |
346 | ||
347 | while (level) { | |
348 | next = sl_level_get(prev, level - 1); | |
349 | if (!next) { | |
350 | level--; | |
351 | continue; | |
352 | } | |
353 | if (next == item) { | |
354 | sl_level_set(prev, level - 1, | |
355 | sl_level_get(item, level - 1)); | |
356 | level--; | |
357 | continue; | |
358 | } | |
359 | cmpval = cmpfn(next, item); | |
360 | if (cmpval < 0) { | |
361 | prev = next; | |
362 | continue; | |
363 | } | |
364 | level--; | |
365 | } | |
366 | ||
367 | /* TBD: assert when trying to remove non-existing item? */ | |
368 | head->count--; | |
369 | ||
370 | if ((uintptr_t)item->next[SKIPLIST_OVERFLOW] & 1) { | |
371 | uintptr_t ptrval = (uintptr_t)item->next[SKIPLIST_OVERFLOW]; | |
372 | ptrval &= UINTPTR_MAX - 3; | |
373 | struct sskip_overflow *oflow = (struct sskip_overflow *)ptrval; | |
374 | XFREE(MTYPE_SKIPLIST_OFLOW, oflow); | |
375 | } | |
376 | memset(item, 0, sizeof(*item)); | |
377 | } |